Project description:Cucumber (Cucumis sativus L.) is an economically important vegetable crop distributed in over 80 countries. Downy mildew (DM) caused by the obligate oomycete Pseudoperonospora cubensis is especially destructive in cucumber production. So far, few studies on the changes in proteomes during the P. cubensis infection have been performed. Using a newly developed TMT-LC-MS/MS analysis, the proteomes of DM-resistant variety ‘ZJ’ and DM-susceptible variety ‘SDG’ under the P. cubensis infection were investigated. In total, 6400 proteins were identified, 5629 of which were quantified. The differential accumulated proteins (DAPs) exhibited various biological functions and diverse subcellular localizations. KEGG enrichment analysis showed that various metabolic pathways were significantly altered under the P. cubensis infection, such as terpenoid backbone biosynthesis, and selenocompound metabolism in ZJ, and starch and sucrose metabolism in SDG. Most of the enzymes associated with terpenoid backbone synthesis were significantly accumulated in ZJ rather than in SDG, suggesting that pathogen-induced terpenoids accumulation might play an important role in the resistance against P. cubensis infection. Furthermore, a number of pathogenesis-related proteins and heat shock proteins were identified as DAPs, suggesting that DM resistance was controlled by a complex network. Our data allowed us to identify and screen more potential proteins related to the DM resistance.
Project description:The regulatory role of miRNA in gene expression is an emerging hot new topic in the control of hypometabolism. Sea cucumber aestivation is a complicated physiological process that includes obvious hypometabolism as evidenced by a decrease in the rates of oxygen consumption and ammonia nitrogen excretion, as well as a serious degeneration of the intestine into a very tiny filament. To determine whether miRNAs play an important regulatory roles in this process, the present study analyzed profiles of miRNA expression in the intestine of sea cucumber (Apostichopus japonicus), using Solexa deep sequencing technology. We identified 309 sea cucumber miRNAs, including 19 novel miRNAs specific to sea cucumber. Animals sampled during deep aestivation (DA) after at least 15 days of continuous torpor, were compared with animals from a non-aestivation (NA) state (animals that had passed through aestivation and returned to an active state). We identified 42 differentially expressed miRNAs (RPM (reads per million) >10, |FC| (|fold change|) M-bM-^IM-%1, FDR<0.01) during aestivation, which were validated by two other miRNA profiling methods: miRNA microarray and real-time PCR. Among the most prominent miRNA species, miR-200-3p, miR-2004, miR-2010, miR-22, miR-252a, miR-252a-3p and miR-92 were significantly over-expressed during deep aestivation compared with non-aestivation animals. Preliminary analyses of their putative target genes suggest that these miRNAs could play important roles in global transcriptional depression during aestivation. In the present study,we present for the first time, using Solexa sequencing technology, an analysis of the global profile of small RNAs in non-aestivation (NA) and deep aestivation (DA) sea cucumbers. We focus on intestine in the present study because it is the major site responsible for the strong metabolic rate depression seen under deep aestivating conditions and the global expression profile of mRNA from the this organ has also been constructed applying RNA-seq technology in our previous study (Zhao and Chen, unpublished data). A preliminary analysis of the functional relevance of miRNA expression in relation to hypometabolism during aestivation is presented. A miRNA microarray and RT-qPCR were both used to supplement and confirm differentially expressed miRNAs. Our findings provide important new insights into the molecular mechanisms of sea cucumber aestivation.